1. The Field of the Invention
The present invention relates generally to radiolucent medical implants, and more specifically to radiolucent bone plates used to stabilize vertebrae or other bones.
2. The Relevant Technology
Bone plates are commonly used for adjusting and/or stabilizing damaged or misaligned bones in the body. For example, spinal stabilizing systems are commonly used in the surgical treatment of spinal fractures or spinal disorders such as degenerative disc disease, disc herniations, scoliosis or other curvature abnormalities. In some cases, dynamic implants are used to preserve motion between vertebral bodies. In other cases, spinal fusion is encouraged to inhibit relative motion between vertebral bodies. Often, a bone plate is used. The bone plate is attached to the exterior of adjacent vertebrae, typically with bone screws, including at a posterior, anterior, or lateral surface of the vertebrae, depending on the circumstances.
A conventional bone screw comprises a threaded shaft having a head mounted on the end thereof. The threaded shaft is inserted through an aperture on the bone plate and screwed into the vertebra. The head is sized so as to be larger than the aperture so that the head then presses against the bone plate as the shaft is screwed into the vertebra, thereby securing the vertebra to the bone plate. To be strong enough to handle the stresses placed upon them, conventional bone screws and bone plates are typically made of titanium or some other high strength, biocompatible metal. As a result of being made of metal, a physician is able to view the bone screws and bone plates using X-ray photographs during and after implantation.
However, the metal bone screws and bone plates also block the X-rays and prevent them from passing through the body. As a result, the metal bone screws and bone plates obscure adjacent bone and other X-ray viewable internal structures surrounding the area, thereby preventing the physician from viewing those structures on an X-ray photograph. This screening can limit a physician's ability to ensure proper placement/orientation of the bone screws and bone plates relative to the surrounding bone structure. Such screening can also hamper the diagnoses and treatment of problems that arise near the location of the bone screws and bone plates after the bone screws and bone plates have been implanted. These same concerns also exist anywhere in the body where a bone plate and accompanying bone screws may be inserted.
Accordingly, what is needed are bone plates that overcome some or all of the above disadvantages.